Hypothesis and Theory: Co-implementing rice husk amendment and alternate wetting and drying irrigation for sustainable rice production

Authors: RUNKLE, B.R.K. - University Of Arkansas; SEYFFERTH, A. - University Of Delaware; REID, MATTHEW - Cornell University; LIMMER, MATTHEW - University Of Delaware; MORENO-GARCIA, BEATRIZ - University Of Arkansas; REAVIS, COLBY - University Of Arkansas; PENA, JASQUELIN - University Of California, Davis; Reba, Michele; Adviento-Borbe, Arlene; Pinson, Shannon; ISBELL, CHRIS - Isbell Farms

Submitted to: Frontiers in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2021
Publication Date: 10/22/2021
Citation: Runkle, B., Seyfferth, A., Reid, M.C., Limmer, M.A., Moreno-Garcia, B., Reavis, C.W., Pena, J., Reba, M.L., Adviento-Borbe, A.A., Pinson, S.R., Isbell, C. 2021. Hypothesis and Theory: Co-implementing rice husk amendment and alternate wetting and drying irrigation for sustainable rice production. Frontiers in Agronomy. 3:741557. https://doi.org/10.3389/fagro.2021.741557.
DOI: https://doi.org/10.3389/fagro.2021.741557

Interpretive Summary: Rice is a staple food and primary source of calories for much of the world. However, it can be a dietary source of toxic metal(loid)s like arsenic and cadmium, and its production enables atmospheric greenhouse gas emissions and requires high water use. We therefore propose a modification to the production system that combines silicon management via re-incorporation of milled rice husks into the soil and water management to grow rice in less flooded soil conditions. Present research shows the promise of both strategies but more research questions are outlined in this perspective as the approach moves from research to field-scale. This paper will be of interest to farmers, researchers, and supply-chain organizations to enhance the sustainability of rice production.

Technical Abstract: Rice is a staple food and primary source of calories for much of the world. However, it can be a dietary source of toxic metal(loid)s, and its production enables atmospheric greenhouse gas emissions and requires high water use. As a significant consumer of natural resources and large part of the global agricultural economy, increasing the sustainability of rice production could have significant benefits. There are opportunities for more sustainable field production through a combination of silicon (Si) management and conservation irrigation practices. Added Si can, among other effects, out-compete arsenic into the rice plant and husk additions can inhibit cadmium uptake while also providing plant vigor in drier soil conditions. Thus, these practices may be more effective together to counter the accumulation of toxic metal(loid)s, manage water usage and lower climate impacts than either separately. This production system would take advantage of rice husks which are an underutilized byproduct of milled rice. The wide availability of rice husks, with ~10% Si content, and their physical proximity to production offer an opportunity for application to paddy soils as a Si amendment. Such application could, alongside alternate wetting and drying or furrow irrigation management, help resolve multiple sustainability challenges in rice production: (1) limit toxic metal(loid) accumulation in rice; (2) minimize greenhouse gas emissions from rice production; (3) reduce irrigation water use; (4) improve nutrient use efficiency; (5) utilize a waste product of rice processing; and (6) maintain plant-accessible soil Si levels. This review presents how such a shift in rice production practices could operate, identifies challenges, opportunities, and synergies to its implementation, and highlights remaining research issues. This review also suggests how farmers and millers would implement this practice together and what this shift would look like from a systems or ‘circular economy’ perspective. This paper’s purpose is to advocate for a changed rice production method for consideration by community stakeholders, including producers, millers, breeders, extension specialists, supply chain organizations, and consumers, while highlighting remaining research questions.